Fig. 6

Oxidative stress assessed with DCF assay after a 24 h exposure of RAW 264.7 mouse macrophages to exhaust gas volume-based doses of PM samples. The Euro 2 doses were one tenth of the doses used with Euro 6. Data reported as mean fold change compared to control cells with standard error of the mean (SEM) and control level is indicated with a dashed line. Asterisks indicate statistically significant differences from the control (Welch’s ANOVA and Dunnett’s t3 test; p < 0.05)